simulation.addChild(hhpop);
simulation.setModified(false);
parentAspect = ((AspectNode) simulation.getParent());
parentAspect.setModified(false);
hhpop.addChild(v);
hhpop.addChild(a1);
SerializeTreeVisitor visitor = new SerializeTreeVisitor();
runtimeTree.apply(visitor);
String serialized = visitor.getSerializedTree();
System.out.println(serialized);